This post has previously disappeared/been disappeared without comment from the main forum for some reason.. There is no commercial interest here, as this is entirely public domain software for all of us.. if anything, the party censoring this may have some vested interest.. I am reposting it here:

I'm surprised OpenCPN has not had any mentions here - it's a free of charge, free software navigation system that is under development but apparently fully usable. Features of the most recent version, 1.3.0, include CM93 vector charts, AIS support and runs on Windows, Mac and Linux.